qt基础之d_ptr和q_ptr
d_ptr和q_ptr
d_ptr在QObject中，q_ptr在QObjectData
//QObject
protected:
QScopedPointer<QObjectData> d_ptr;
//QObjectData
class Q_CORE_EXPORT QObjectData {
public:
virtual ~QObjectData() = 0;
QObject *q_ptr;
QObject *parent;
QObjectList children;
uint isWidget : 1;
uint blockSig : 1;
uint wasDeleted : 1;
uint isDeletingChildren : 1;
uint sendChildEvents : 1;
uint receiveChildEvents : 1;
uint isWindow : 1; //for QWindow
uint unused : 25;
int postedEvents;
QDynamicMetaObjectData *metaObject;
QMetaObject *dynamicMetaObject() const;
}
QObjectData
+QObject *q_ptr
+QObject *parent
+QObjectList children
+uint isWidget
+uint blockSig
+uint wasDeleted
+uint isDeletingChildren
+uint sendChildEvents
+uint receiveChildEvents
+uint isWindow
+uint unused
+int postedEvents
+int postedEvents
+QDynamicMetaObjectData *metaObject
QObjectPrivate
+ExtraData *extraData
+QThreadData *threadData
+QObjectConnectionListVector *connectionLists
+Connection *senders
+Sender *currentSender
+mutable quint32 connectedSignals[2]
+QAtomicPointer sharedRefcount
ExtraData
+QVector userData
+QList propertyNames
+QList propertyValues
+QVector runningTimers
+QList > eventFilters
+QList > eventFilters
+QString objectName
QThreadData
-QAtomicInt _ref
+int loopLevel
+QStack eventLoops
+QPostEventList postEventList
+QThread *thread
+HANDLE threadId
+QAtomicPointer eventDispatcher
+QVector tls
+FlaggedDebugSignatures flaggedSignatures
+bool quitNow
+bool canWait
+bool isAdopted
Connection
+QObject *sender
+QObject *receiver
+Connection *nextConnectionList
+Connection *next
+Connection **prev
+QAtomicPointer argumentTypes
+QAtomicInt ref_
+ushort method_offset
+ushort method_relative
+uint signal_index
+ushort connectionType
+ushort isSlotObject
+ushort ownArgumentTypes
Sender
+QObject *sender
+int signal
+int ref
QObjectConnectionListVector
d_ptr：表示类的具体实现类
q_ptr：表示具体实现类的所属类
QObject中的d_ptr是在构造函数时初始化的，同时QObjectPrivate中的d_ptr也会初始化
QObject::QObject(QObject *parent)
: d_ptr(new QObjectPrivate)
{
Q_D(QObject);
d_ptr->q_ptr = this;
d->threadData = (parent && !parent->thread()) ? parent->d_func()->threadData : QThreadData::current();
d->threadData->ref();
if (parent) {
QT_TRY {
if (!check_parent_thread(parent, parent ? parent->d_func()->threadData : 0, d->threadData))
parent = 0;
setParent(parent);
} QT_CATCH(...) {
d->threadData->deref();
QT_RETHROW;
}
}
if (Q_UNLIKELY(qtHookData[QHooks::AddQObject]))
reinterpret_cast<QHooks::AddQObjectCallback>(qtHookData[QHooks::AddQObject])(this);
Q_TRACE(QObject_ctor, this);
}
相关宏
Q_DECLARE_PRIVATE：在具体实现类的所属类中使用，表示获取对应的私有实现类的指针，同时将私有实现类声明为友元的
Q_DECLARE_PRIVATE_D：在Q_DECLARE_PRIVATE基础上指定了私有实现指针
Q_D：是对Q_DECLARE_PRIVATE中定义的d_func的调用
#define Q_DECLARE_PRIVATE(Class) \
inline Class##Private* d_func() \
{ Q_CAST_IGNORE_ALIGN(return reinterpret_cast<Class##Private *>(qGetPtrHelper(d_ptr));) } \
inline const Class##Private* d_func() const \
{ Q_CAST_IGNORE_ALIGN(return reinterpret_cast<const Class##Private *>(qGetPtrHelper(d_ptr));) } \
friend class Class##Private;
#define Q_DECLARE_PRIVATE_D(Dptr, Class) \
inline Class##Private* d_func() \
{ Q_CAST_IGNORE_ALIGN(return reinterpret_cast<Class##Private *>(qGetPtrHelper(Dptr));) } \
inline const Class##Private* d_func() const \
{ Q_CAST_IGNORE_ALIGN(return reinterpret_cast<const Class##Private *>(qGetPtrHelper(Dptr));) } \
friend class Class##Private;
#define Q_D(Class) Class##Private * const d = d_func()
Q_DECLARE_PUBLIC：定义了q_func普通指针和常指针版本的函数，返回私有类的所属类，同时声明所属为在友元类
Q_Q：对Q_DECLARE_PUBLIC中定义的q_func函数的调用
#define Q_DECLARE_PUBLIC(Class) \
inline Class* q_func() { return static_cast<Class *>(q_ptr); } \
inline const Class* q_func() const { return static_cast<const Class *>(q_ptr); } \
friend class Class;
#define Q_Q(Class) Class * const q = q_func()